For example, Japanese Unexamined Patent Publication No. 2007-290798 (hereinafter, referred to as “Patent Literature 1”) discloses a cabin support deck which supports a cabin of a construction machine on the underside of the cabin as illustrated in FIGS. 5 and 7. The cabin support deck described in Patent Literature 1 has a configuration in which a proximal portion of the support deck is supported to a machine body.
With the cabin support deck, for example, a weight reduction is likely to lead to a lack of necessary dynamic stiffness. To the contrary, an increase of the thickness of the cabin support deck to enhance the dynamic stiffness is likely to lead to an increase of the weight of the cabin support deck.